1. Field of the Invention
The present invention relates generally to flexible elastomer articles and methods of making the same in which the articles contain a moisturizing and/or therapeutic material or materials incorporated into an elastomer(s) from which the article is made or coated on the wearer contacting surface of the article, or both. More particularly, the invention relates to, in one aspect, elastomer(s) modified with the addition of botanical extracts in order to enhance the physical and therapeutic properties of articles made from these materials. In a second aspect, the invention relates to coating surfaces of flexible elastomer articles to improve skin or mucosa moisturizing properties and donnability with a non-Aloe vera coating material of a mucinous botanical or laboratory produced polysaccharide which is fortified by additives known to protect and restore mammalian skin. A third aspect of the invention combines the first and second aspects. Flexible elastomer articles include gloves and other single layer or multi-layer flexible elastomer articles, e.g., catheters, stents, incontinence devices having a sheath or sheath type construction, condoms, cervical caps, diaphragms, dental dams, elastomer sheets, balloons for use in medical devices, sheaths or tubes used for medical devices, and finger cots.
Disposable gloves are widely used by members of the medical community, the scientific community, and the industrial community to protect the wearer from chemical exposure, mechanical abrasion, environmental hazards, biohazard contamination and to prevent transmission of disease or contaminants. Health care providers frequently wear disposable gloves while performing surgery or other medical or dental procedures such as patient examinations; thus, the gloves are often also referred to as disposable examination gloves or disposable surgical gloves. The disposable gloves are impermeable to biological fluids, tissues and solids produced by the body or other contaminants (human or animal) advantageously protecting the wearer from fomitic (transmission by objects that harbor pathogenic organisms) transmission of pathogens and disease.
Also, disposable gloves are worn by individuals who wish to protect their hands from various chemicals, materials and objects which may irritate, damage or dry out the users skin and which may be harmful or potentially harmful if allowed to contact or permeate the dermal barrier. These gloves may be worn in the occupational setting by scientists, cleaning service workers, food handlers, law enforcement workers, beauticians or other workers having special protection needs. Thus, disposable gloves may also be referred to as protective gloves or industrial gloves. Also some disposable gloves are considered reusable gloves because they can be used multiple times prior to disposal. For example, homemakers may reuse the same pair of household gloves to protect their hands from harsh cleaning solutions or just while doing dishes. Likewise, gardeners or plant service workers may reuse gloves when spraying plants with fungicides or other garden chemicals.
It is desirable that the gloves (disposable and/or reusable) provide the necessary protection, are durable, flexible, do not cause irritation or allergy problems to those in contact with the article, are not tacky, are easy to don, and are comfortable to wear. Unfortunately, sometimes the desirable characteristics are not achieved.
As is known in the art, disposable gloves (and reusable gloves as well as other flexible elastomer articles) are thin and flexible and are manufactured from a variety of polymeric materials herein throughout referred to as “elastomer(s)” or “elastomer material(s)” or “raw material(s)”. These elastomers may be considered a natural rubber as with natural rubber latex (NRL) or a synthetic rubber, or a plastic and include, but are not limited to, a synthetic polyisoprene, a chloroprene (including Neoprene-homopolymer of the conjugated diene chloroprene), a polyurethane (PU), a polyvinyl chloride (PVC), a styrene butadiene styrene (SBS), a styrene isoprene styrene (SIS), a silicone, a butadiene methylmethacrylate, an acrylonitrile, a styrene ethylene butylene styrene (SEBS), an acrylate-based hydrogel, any other elastomer that can be suspended into an emulsion, any other elastomer that is suspendable, soluble or miscible in a solution or plastisol, and combinations thereof.
As is known in the art, disposable gloves (and reusable gloves) are manufactured of elastomer(s) as single layer gloves or multi-layer gloves. A single layer glove has one layer having a single or blended (or mixture of) elastomer material therein. The one layer has an outer surface (or distal surface) and an opposite wearer-contacting surface. The wearer-contacting surface may have a material coated, dusted, sprayed or otherwise adhered thereon which functions to detackify the article during processing preventing sticking together in storage and/or to facilitate donning of the gloves by serving as a donning agent and providing enhanced lubricity on the wearer contacting surface thereby reducing frictional forces.
The multi-layer glove has more than one layer. One type of multi-layer glove is a bilaminar glove, which has two layers, namely a first layer and a second layer. The two layers are of similar or dissimilar elastomer(s). The first layer is a substrate layer having an elastomeric material and a distal surface and the second layer is a layer having a wearer-contacting surface. The bilaminar glove is commonly manufactured to have the thickness and the flexibility of the single layer glove. The materials used in the flexible disposable gloves or reusable gloves (collectively “gloves”) and other flexible articles are elastomers compoundable as emulsions, solutions or plastisols wherein the elastomers are suspendable, soluble or miscible. For example, the materials used in the second layer of the bilaminar gloves are known in the art. See U.S. Pat. No. 3,286,011 to Kavalir et al., which discloses a mixture of an elastomer latex and a latex of a resin dipped on an elastomer latex to form an adherent elastomer-resin film on the elastomer article.
Other types of multi-layer gloves may have three or more layers, with one layer bearing the wearer contacting surface, and another layer bearing the distal surface with one or more intervening layers between the two layers having the wearer contacting surface and distal surface. Similarly, other flexible elastomer articles may have one or more layers of elastomer (or mixtures of elastomers) with one layer having the wearer-contacting surface and the same layer (if a single layer) or another layer having the distal surface (if a multi-layer article).
Some known in the art methods of making flexible elastomer gloves and glove materials are for example, U.S. Pat. No. 6,465,591, to Lee; U.S. Pat. No. 6,440,498, to Scholar; U.S. Pat. No. 6,423,328, to Chou; U.S. Pat. No. 6,414,083, to Plamthottam; U.S. Pat. No. 6,391,409, to Yeh et al.; U.S. Pat. No. 6,380,283, to Perella, et al.; U.S. Pat. No. 6,369,154, to Suddaby; U.S. Pat. No. 6,347,408, to Yeh; U.S. Pat. No. 6,345,394, to Nakamura, et al.; U.S. Pat. No. 6,306,514, to Weikel, et al.; U.S. Pat. No. 6,288,159, to Plamthottam; U.S. Pat. No. 6,284,856, to Lee; U.S. Pat. No. 6,280,673, to Green, et al.; U.S. Pat. No. 6,274,154, to Chou; U.S. Pat. No. 6,254,947, to Schaller; U.S. Pat. No. 6,242,042, to Goldstein, et al.; U.S. Pat. No. 6,221,447, to Munn, et al.; U.S. Pat. No. 6,213,123, to Miller, et al.; U.S. Pat. No. 6,121,366, to Sharma; U.S. Pat. No. 6,066,697, to Coran, et al.; U.S. Pat. No. 6,031,042, to Lipinski; U.S. Pat. No. 6,019,922, to Hassan, et al.; U.S. Pat. No. 6,017,997, to Snow, et al.; U.S. Pat. No. 6,016,570, to Vande Pol et al.; U.S. Pat. No. 6,000,061, to Taneja, et al.; U.S. Pat. No. 5,997,969, to Gardon; U.S. Pat. No. 5,993,923, to Lee; U.S. Pat. No. 5,985,955, to Bechara, et al.; U.S. Pat. No. 5,974,589, to Pugh et al.; U.S. Pat. No. 5,965,276, to Shlenker, et al.; U.S. Pat. No. 5,910,533, to Ghosal, et al.; U.S. Pat. No. 5,900,452, to Plamthottam; U.S. Pat. No. 5,881,387, to Merovitz, et al.; U.S. Pat. No. 5,881,386, to Horwege et al.; U.S. Pat. No. 5,877,244, to Hoover, et al.; U.S. Pat. No. 5,869,072, to Berry; U.S. Pat. No. 5,851,683, to Plamthottam, et al.; U.S. Pat. No. 5,833,915, to Shah; U.S. Pat. No. 5,807,941, to Tsuji et al.; U.S. Pat. No. 5,742,943, to Chen; U.S. Pat. No. 5,741,885, to Dove; U.S. Pat. No. 5,712,346, to Lee; U.S. Pat. No. 5,708,132, to Grimm; U.S. Pat. No. 5,700,585, to Lee; U.S. Pat. No. 5,691,446, to Dove; U.S. Pat. No. 5,691,069, to Lee; U.S. Pat. No. 5,682,613, to Dinatale; U.S. Pat. No. Re. 35,616, to Tillotson, et al.; U.S. Pat. No. 5,651,995, to Oyama et al.; U.S. Pat. No. 5,644,798, to Shah; U.S. Pat. No. 5,620,773, to Nash; U.S. Pat. No. 5,614,202, to DeFina; U.S. Pat. No. 5,612,083, to Haung et al.; U.S. Pat. No. 5,601,092, to Miller, et al.; U.S. Pat. No. 5,598,850, to Miller, et al.; U.S. Pat. No. 5,570,475, to Nile et al.; U.S. Pat. No. 5,568,657, to Cordova, et al.; U.S. Pat. No. 5,483,697, to Fuchs; U.S. Pat. No. 5,459,879, to Fuchs; U.S. Pat. No. 5,458,936, to Miller, et al.; U.S. Pat. No. 5,444,121, to Grennes, et al.; U.S. Pat. No. 5,407,715, to Buddenhagen, et al.; U.S. Pat. No. 5,405,690, to Hirakawa; U.S. Pat. No. 5,405,666, to Brindle; U.S. Pat. No. 5,395,666, to Brindle; U.S. Pat. No. 5,370,915, to Hirakawa; U.S. Pat. No. 5,284,607, to Chen; U.S. Pat. No. 5,272,771, to Ansell, et al.; U.S. Pat. No. 5,215,701, to Gould, et al.; U.S. Pat. No. 5,112,900, to Buddenhagen, et al.; U.S. Pat. No. 5,088,125, to Ansell, et al.; U.S. Pat. No. 5,020,162, to Kersten, et al.; U.S. Pat. No. 5,014,361, to Gray; U.S. Pat. No. 5,001,354, to Gould et al.; U.S. Pat. No. 4,954,309, to McGlothlin, et al.; U.S. Pat. No. 4,917,850, to Gray; U.S. Pat. No. 4,696,065, to Elenteny; U.S. Pat. No. 4,575,476, to Podell, et al.; U.S. Pat. No. 4,548,844, to Podell et al.; U.S. Pat. No. 4,499,154, to James, et al.; U.S. Pat. No. 4,482,577, to Goldstein, et al.; U.S. Pat. No. 4,463,156, to McGary, Jr., et al.; U.S. Pat. No. 4,390,492, to Kurtz; U.S. Pat. No. 4,371,988, to Berend; U.S. Pat. No. 4,340,348, to Kurtz; U.S. Pat. No. 4,302,852, to Joung; U.S. Pat. No. 4,251,574, to Berend; U.S. Pat. No. 4,186,445, to Stager; U.S. Pat. No. 4,185,330, to Stager; U.S. Pat. No. 4,070,713, to Stockum; U.S. Pat. No. 4,061,709, to Miller et al.; U.S. Pat. No. 3,942,193, to Pugh; U.S. Pat. No. 3,933,723, to Grenness; U.S. Pat. No. 3,813,695, to Podell, Jr. et al.; U.S. Pat. No. 3,397,265, to H. N. Ansell; U.S. Pat. No. 3,286,011, to Kavalir et al.; U.S. Pat. No. 3,225,360, to Keilen, Jr., et al.; U.S. Pat. No. 3,059,241, to O'Brien, et al.; U.S. Pat. No. 3,025,403, to Belknap, et al.; U.S. Patent Application Publication No. 2002/0110584, to Chou; U.S. Patent Application Publication No. 2002/0025335, to Chou; and U.S. Patent Application Publication No. 2001/0048937 A1, to Chou; PRC (Peoples Republic of China) ZL 95 2 22651.0 (Applicant: Gin Bao Shan enterprises Co. Ltd.), all of which are hereby incorporated herein by reference.
As is known in the art, the ASTM, (American Society for Testing and Materials, ASTM International, West Conshohocken, Pa., USA) and ISO (International Organization for Standardization, Geneva, Switzerland) provide standard specifications for disposable and reusable gloves. The standard specifications include performance requirements such as, but not limited to, freedom from holes, physical dimensions, physical properties, and total and/or antigen protein content. The standards include, but are not limited to, ASTM D 3577-01aε2 “Standard Specification for Rubber Surgical Gloves”, ASTM D 3578-01aε2 “Standard Specification for Rubber Examination Gloves”, ASTM D 5250-00ε4 “Standard Specification for Poly(vinyl chloride) Gloves for Medical Application” and ASTM D 6319-00aε3 “Standard Specification for Nitrile Examination Gloves for Medical Application”, ISO 10282:2002(E) “Single-use sterile rubber surgical gloves-Specification”, ISO 11193:2002(E) “Single-use medical examination gloves-Part 1: Specification for gloves made from rubber latex or rubber solution”, ASTM F 1671-97b “Standard Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Blood-Borne Pathogens Using Phi-X174 Bacteriophage Penetration as a Test System”, ASTM D 5151-99 “Standard Test Method for Detection of Holes in Medical Gloves”, ASTM D 6499-00 “Standard Test Method for The Immunological Measurement of Antigenic Protein in Natural Rubber and its Products”, ASTM D 412-98a “Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers—Tension”, ASTM D 4679-02 “Standard Specification for Rubber General Purpose, Household or Beautician Gloves”, ASTM D 5712-99 “Standard Test Method for The Analysis of Aqueous Extractable Protein in Natural Rubber and Its Products Using the Modified Lowry Method”, ASTM D 573-99 “Standard Test Method for Rubber—Deterioration in an Air Oven”, ASTM D 6124-01 “Standard Test Method for Residual Powder on Medical Gloves”, ASTM D 6355-98 “Standard Test Method for Human Repeat Insult Patch Testing of Medical Gloves”, and ASTM D 3767-01 “Standard Practice for Rubber—Measurement of Dimensions”, all of which are hereby incorporated herein by reference.
The gold standard elastomer for flexibility and comfort in disposable medical and industrial gloves (reusable gloves and other flexible articles) since the turn of the last century has been NRL which is harvested from the rubber tree Hevea brasiliensis. The NRL is synthesized within the cytoplasm of the laticifer cell of the rubber tree by a series of enzymes bathed in a complex milieu of minerals, amino acids, proteins, lipids, polysaccharides, etc., e.g., collectively referred to herein as “botanical contents”. The liquid NRL harvested from the tree including the aforementioned botanical contents from the laticifer cells is then compounded or blended with a variety of processing chemicals. It is this blended NRL emulsion that is coagulated on the surface of a hand shaped former (in the case of glove manufacture) by a process known in the art as “dipping” (other flexible articles may be produced by dipping, molding or extrusion). Depositing the NRL emulsion evenly on the surface of the former is accomplished by pre-treating the former with a chemical anticoagulant (typically calcium nitrate or similar salt). The anticoagulant is applied to the former by dipping and is then oven dried.
The result is a fine salt crystal layer over the surface of the former. The salt layer thickness and composition together with the emulsion viscosity, NRL particle concentration, and dwell time in the NRL emulsion tank determine the thickness of the finished glove. This salt pretreated former then dips into the liquid NRL emulsion tank. The presence of the anticoagulant on the surface initiates coagulation of the NRL emulsion. As the former is removed from the NRL dip tank emulsion, the coagulation is not 100% complete. The non coagulated NRL begins to flow due to gravitational forces.
For this reason most machines are designed so the former immediately begins rotating on an axis parallel to the length of the former and completes a 90 to 180 degree rotation from the base of the former before entering the vulcanization ovens. The former rotation is trying to manage the unwanted flow of the yet uncoagulated NRL emulsion in order to minimize thickness variability in the finished product. Poor coordination of coagulation chemistry, emulsion viscosity, NRL density and rotation patterns of the formers produces a glove which when blown up shows a river like pattern where thicker rubber tributaries can be seen migrating from areas where there was pooled uncoagulated NRL which flowed randomly before coagulating. This uncontrolled flow produces finished products with thin and thick spots (non-uniformity of article layer, e.g., here the glove layer) which have increased vulnerability to breakage in use, greater susceptibility to oxidative damage in storage and are cosmetically less pleasing to the user. Even with optimal coordination of the variables some flow of the NRL occurs prior to coagulation producing variability of thickness of the finished product particularly at the finger tips.
Accordingly if a material could be selected that imparted thixotropic properties which could minimize this unwanted gravitational flow of the uncoagulated NRL without compromising the other variables of the process, an advantageous result of providing a more consistent thickness could be achieved with the finished product. The aforementioned methods of depositing a NRL emulsion on a former and the problem associated with production of a uniform article layer are also associated with other elastomers which can be suspended into an emulsion. In addition to NRL, such elastomers include a synthetic polyisoprene, a chloroprene, a PU, an acrylonitrile, a butadiene methylmethacrylate, an SBS, an SIS, an SEBS, a silicone, an acrylate-based hydrogel, any other elastomer that can be suspended into an emulsion, and mixtures thereof (all of which are currently commercially available as an emulsion with the exception of SBS, SIS, SEBS). If said material could be added to other elastomers, unwanted flow of the uncoagulated, unpolymerized or undried emulsions would result in a finished article (e.g. glove or other flexible elastomer article) with a more uniform thickness.
In 1986, OSHA published the Universal Bloodborne Pathogen Guideline for the specific purpose of minimizing the risk of the transmission of infection from patient to employee in the context of delivering healthcare. AIDS and Hepatitis B were of particular concern. The wearing of single use disposable gloves was a key part of this guideline and resulted in an exponential increase in both the frequency and duration of use of NRL gloves. An unfortunate consequence was a significant increase in the incidence of glove allergies (for a discussion of allergy problems, see, Hamann et al. “Allergies Associated with Medical Gloves—Manufacturing Issues” (1994) Occupational Dermatoses, Vol. 12, No. 3, pp. 547-599, incorporated by reference herein). Prior to glove users developing particular life threatening IgE specific antibodies against antigenic proteins originating from the laticifer cytoplasm of the rubber tree, a significant proportion of the laticifer cell cytoplasmic contents persisted in a finished NRL glove.
In the early nineties, in an effort to reduce the antigenic protein concentration in NRL gloves, processes were developed to remove or reduce the NRL botanical contents within the emulsions used to produce NRL products. Unfortunately, the broad variety of cytoplasmic contents that were now being removed contained natural botanical waxes, lipids and polysaccharides which synergistically functioned as plasticizers. These natural plasticizers affected the modulus (softness) of the finished product and allowed for a strong, yet supple glove. A lower modulus product is preferred by glove users because of its relation to the comfort and fit of the finished article. This user preferred softness of an NRL glove is compromised by the removal of the botanical contents and is impossible to replicate with synthetic elastomers.
Furthermore, the minerals, amino acids, proteins, lipids, waxes, polysaccharides, together with hundreds of additional unique botanical molecules (botanical contents) also function as excellent emulsifiers to assist in the optimal uniform distribution of the NRL particles in a dip tank making the deposition of a uniform film on the porcelain former easier. In addition, numerous naturally occurring antioxidants (amino acids, proteins, etc.) are available in the botanical contents that serve to protect the vulnerable unsaturated carbon bonds of the NRL by scavenging for free radicals throughout the useful life of the product. These molecules bloom to the surface over time and function as competitive inhibitors to the destruction of the NRL unsaturated bonds. Oxidized glove surfaces increase breakage while donning and during use. While removal or inactivation of the antigenic proteins has been necessary, the disadvantage has been the simultaneous elimination of the many benefits the remaining molecules of the botanical extract provide.
Accordingly if the botanical contents of the laticifer cells could be replaced in the NRL emulsion by a material without cross reactive antigenic proteins, the benefits of a more stable dipping emulsion with improved flow properties would be realized and a finished article with lower modulus and improved oxidative protection would be restored. If the material could be chosen which also contained dermatologically therapeutic components, the finished product would be enhanced. Furthermore, if the material could be added to synthetic elastomers used to produce gloves (or other flexible elastomer articles), the physical properties would have the ability to more closely mimic the preferred attributes of NRL.
Flexible elastomer articles, like disposable gloves, are frequently changed by the wearer during the day between patients or between procedures or activities. Allergy and irritation potential of a finished glove has been exacerbated by common glove manufacturing practices of using vulcanizing accelerators, antioxidants, cornstarch powder and other additives as means to speed production, ease donnability, prevent tackiness and enhance durability during the storage and useful life of the glove. In addition, since disposable gloves cover the hand, moisture (perspiration) is trapped beneath the glove, contributing to hand dermatitis. As a result, in excess of 20% of healthcare providers struggle with an allergic or irritant contact dermatitis or the IgE mediated latex antigen hypersensitivity (Type I) thereby making these individuals more susceptible to infection.
Solutions to the tackiness and donning problems are coating the wearer-contacting surface with a powder, halogenation, or other surface treatments. (See U.S. Pat. No. 4,186,445 and U.S. Pat. No. 4,185,330, both to Stager, and U.S. Pat. No. 5,614,202 to DeFina.) Cornstarch is used because most polymers are intrinsically sticky on their surfaces causing a blocking affect which makes it difficult to don the glove without the powder. (Other powders used in the interior of the glove to lubricate the glove, include, but are not limited to, talcum powder, starch dusting powder, polyglycolic acid powder, insoluble sodium metaphosphate powder, magnesium carbonate, oat starch and granular vinyl chloride polymer.) The powder may provide comfort to the wearer's hand as the hand moisture builds up within the glove as the glove is used but conversely may also act to dry, abrade and irritate the user's skin.
Although many glove users apply lotions and creams to moisturize their hands, these emollients frequently are oil-based which deleteriously affects an NRL glove. Further, these creams and lotions often contain similar antigenic chemicals and serve to exacerbate the skin problems.
It has also been shown that the antigenic proteins bloom to the surface of the NRL glove (or other flexible article) and migrate into the powder particles which then serve as vehicles to carry the antigen. This has been shown to be most problematic as an aerosolized particle delivered during breathing to the immunoactive tissue of the nasopharynx and bronchial tree where sensitization and elicitation of Type I NRL reactions can be initiated. In addition, glove powders can cause skin irritation and exacerbate contact allergies, therefore, the reduction or elimination of glove powders help glove users maintain a healthy dermal barrier and assure optimal protection against pathogens and contaminants which is the intended purpose of the glove.
The need to eliminate or minimize residual glove powder has led to the development of various powder removal processes and of alternative glove coatings. To remove unwanted powders, gloves are sometimes treated to a chlorination and neutralization process. Although these processes remove unwanted powder they also halogenate the glove surface and deleteriously affect the physical properties of the glove by accelerating the oxidation process by cleaving the unsaturated carbon bonds of the NRL polyisoprene chain, thus decreasing the shelf life and the softness of the glove.
The chlorination treatment of the glove may be used with or without the additional coating or lubricant composition treatment (see U.S. Pat. No. 5,742,943 to Chen for use of a lubricant composition post chlorination, where the lubricant composition has a first and a second composition, where the first composition comprises an acetylenic diol and at least one compound selected from the group consisting of an organo-modified silicone, an amino-modified silicone, and 1-hexadecylpyridiniuni chloride monohydrate, and the second composition comprises 1-hexadecylpyridium chloride monohydrate and at least one compound selected from the group consisting of an organo-modified silicone, an amino-modified silicone, and an acetylenic diol).
The art has responded to the problems associated with powder by preparing powderless gloves by the use of alternative lubricants, such as, polymeric lubricant coatings which are bonded to the tissue-contacting surface of the glove or are adhered to the elastomer, NRL (natural or synthetic) or plastic itself (See, for example, U.S. Pat. No. 4,548,844 to Podell et al. flexible rubber article with an interior lining of hydrophilic plastic material, preferably a hydrogel plastic material and U.S. Pat. No. 3,813,695 to Podell, Jr. et al. flexible glove with inner layer of a hydrophilic plastic material; U.S. Pat. No. 6,019,922 to Hassan et al. dip coating over an elastomer layer formed of an antiblocking composition comprising a polymer/co-polymer (such as an anionic aliphatic polyether polyurethane, or a co-polymer of vinylidene chloride/methyl acrylate, or natural rubber polymer), a high density polyethylene particle and a wax (such as a mixture of carnuba wax/paraffin wax); U.S. Pat. No. 5,395,666 to Brindle, use of porous, absorbent microparticles, preferably silica, added to a binder material having good adhesion to both an elastomeric substrate and to the microparticles; U.S. Pat. No. 5,881,386 to Horwege et al. a polyester polyurethane having a texturizing agent selected from the group consisting of diatomaceous earth, silica, glass beads and calcium carbonate, is adhered to a plasticized polyvinyl chloride resin film; U.S. Pat. No. 5,974,589 to Pugh et al. use of high density substantially linear hydrocarbon polymer, (such as polyethylene, polypropylene, polymethylene, paraffin, low density polyethylene, or a mixture thereof) to adhere to the surface of a latex article such as a glove; U.S. Pat. No. 5,570,475 to Nile et al., use of polymers on the hand contacting surface (such as, copolymers of a vinyl alkyl ether and a maleic ester or copolymers, of an alkylene and a maleic ester, or of copolymers of vinyl methyl ether and a maleic ester, or polymers of a butyl half ester of polyethylene/maleic acid, or a butyl half ester of polystyrene/maleic acid, of a partly esterified poly(styrene/maleic acid)) or polymers sold under the name SCRIPTSETS (available from Monsanto) to form a polymer layer on a natural or synthetic elastomer surface, with optional use of surfactant (cetyl pyridinium chloride) treatment, with or without use of silicones. Others have used different materials to form the glove, e.g., see U.S. Pat. No. 4,061,709 to Miller et al. for silicone rubber gloves.
Coating the gloves with alternative lubricants (glove coatings) present challenges because coatings are difficult to apply to a glove with a dip, spray, spray and tumble (spray/tumble), or soaking process. Because of the relative hydrophobicity of the surface of most gloves, the coatings tend to bead and concentrate in dependent areas of the glove resulting in uneven application of the coating.
For an example of a spray deposition process to impart an interior texture to the flexible glove see U.S. Pat. No. 6,016,570 to Vande Pol et al. Others have used multiple layers having a first layer of natural rubber or polyurethane, chloroprene, styrene/butadiene copolymer, nitrile latex, a second layer of natural rubber, polyurethane, poly(acrylamide-acrylic acid, sodium salt) and polyethyleneoxide, and a third wearer-contacting layer of acrylic copolymer and flurocarbon telomer resin, or alternatively a first layer of plastisol polyvinyl chloride (PVC) and coating this with the aforementioned wearer contacting layer, e.g., see U.S. Pat. No. 5,612,083 to Haung et al. Other bilaminar (two-layer) glove processes include PRC Patent ZL95 2 22651.0 disclosing a powder free process of manufacturing PVC gloves where a polyvinyl chloride substrate is given a slip surface treatment in a water base process or in an oil-base process. In the water base process, a water based silicone oil and catalyst form a film coating on the PVC substrate. In the oil base process, a polyester having good water solubility is used for the polyurethane epoxy along with a mixture of methy-ethyl-ketone/isobutyl-ketene and isopropyl alcohol to form the film coating on the PVC substrate.
Accordingly if a coating material could be chosen for application to a glove surface (or other flexible article surface) which produces acceptable donning attributes without the need for cornstarch as a donning agent, the transmission of the NRL antigenic protein would be minimized. If the thixotropic properties of the coating material were such that the coating functioned more like a liquid biopolymer, it would reduce the beading and pooling of the coating, and allow a uniform coating to be applied over all the glove (or other flexible article), and the product would be improved. If the coating material uniformly distributed could also simultaneously optimize moisture homeostasis between the glove and epidermis of the wearer to minimize irritant contact dermatitis from the extremes of dryness and wetness, a contribution would be made in reducing the risk of infection of damaged skin. If said uniformly distributed coating material also partially solubilizes during use and delivers therapeutically important molecules to mitigate the risks of irritant and contact dermatitis, the user will benefit from added protection. If the coating material also functions as a microbicide, an additional important level of protection could be provided if the glove were to fail and skin exposure to a pathogen occurred.
Furthermore, if said coating material could be applied to the surface of synthetic gloves and act as a donning agent by improving donning without powder, and decrease irritant and allergic contact dermatitis, and provide a microbicide in the case of glove (or other flexible article) failure, a contribution will be made. Also, if said coating material could balance moisture under the surface of the glove, a further contribution will be made.
U.S. Pat. No. 6,274,154 and U.S. Pat. No. 6,423,328, both to Chou and both incorporated herein by reference, U.S. Patent Application Publication No. 2001/0048937 A1, U.S. Patent Application Publication No. 2002/0025335 A1, and U.S. Patent Application Publication No. 2002/0110584 A1, all to Chou and all three of which are incorporated herein by reference, disclose a flexible single layer disposable glove containing dehydrated Aloe vera on the wearer contacting surface and a method of manufacturing the glove. The method of manufacturing the gloves discloses the steps of: forming an NRL glove, turning the glove inside out, applying an aqueous solution of Aloe vera to the surface facing out, removing the liquid by a controlled dehydration process with heat tumble drying of the gloves and/or the use of forced heated air to provide a partially and preferably full or at least substantial dehydration of the Aloe vera solution in the gloves, and turning the glove right side out so the dehydrated coating of Aloe vera contacts the hand of the glove wearer.
When the gloves are worn, the dehydrated Aloe vera is dissolved by the moisture from the wearer's hand. Aloe vera is a plant, long looked to in folk medicine for skin care and has been used in skin care products for moisturizing the upper layers of the epidermis of the skin. (See U.S. Pat. No. 5,800,818 to Prugnaud et al.) Despite the advantages of using Aloe vera as a coating material, for glove manufacturers competing in the international glove industry, the cost of the Aloe vera becomes an important consideration in competing globally.
What is needed is a flexible elastomer article, such as a disposable or reusable glove, having materials incorporated within its elastomer matrix that serve as a stabilizer, a flow modifier, an emulsifier, a plasticizer, a humectant, and an antioxidant. As a stabilizer, the material should stabilize the emulsion of the elastomer(s) by maintaining dispersions of otherwise imiscible phases and inhibiting physical processes (e.g., sedimentation, trapping gas bubbles and the non-uniform dispersion of rubber particles) within the emulsion of the elastomer(s), allowing for a more uniform film deposition during the dipping process. Additionally, the material should function as a flow modifier by providing selected thixotropic properties that modify the rheology of the elastomer emulsion thereby decreasing unwanted flow of the emulsion when forming the article. The material should also serve as an emulsifier by actively reducing surface tension thereby improving film deposition at the time of dipping. The material should act as a plasticizer by lowering the modulus of the finished article resulting in a softer glove (or other article) with retained strength and improved wearer comfort. The material should act as a humectant by balancing moisture homeostasis thereby enhancing skin moisturizing properties, lubricity and donning characteristics of the flexible article. The material should act as an antioxidant preventing unwanted oxidation during manufacturing and improving the shelf life of the finished article by protecting the vulnerable unsaturated carbon bonds of the elastomer.
A need exists to provide a flexible elastomer article with improved shelf life having a wearer contacting surface with improved moisturizing properties, lubricity and donning characteristics, and which provides comfort to the wearer.
A need also exists to provide a more economical method of fabricating a flexible elastomer article with improved lubricity and donning characteristics, with improved shelf life and which provides comfort to the wearer.
Yet another need exists to provide a flexible elastomer article utilizing raw materials which yield cost saving to the manufacturer without compromising the attributes of the finished product and which provide decreased bioburden in the finished product.